Specific variations in personal genes among study participants played a part in determining the efficacy of an HIV vaccine that was moderately successful among Thai volunteers, Science Daily reports. Publishing their findings in Science Translational Medicine, researchers examined the effect of immune response genes in the RV144 vaccine trial.

The HLA class II molecules to which these genes give rise are an important part of the body’s antibody response system. The researchers looked at variations in the genes to see how they interacted with two other vaccine-induced elements that correlated with HIV risk in the trial. They found that the HLA class II genes affected both the quantity and quality of antibody responses that the vaccine prompted, which in turn affected individuals’ likelihood of acquiring the virus.

To read a press release about the study, click here.

To read the study abstract, click here.